Focal plane shutter



July 2, 1940. o. WITTEL FOCAL PLANE SHUTTER Original Filed April 12, 1938 3 Sheets-Sheet 1 :L. 7 3 TR 5 2M2 LQWS Tm n :1 mm m A. r V O \R N m 5 w .0 W W l m M a 8 0 I 3 m 3 x 1 a m m a n Flo 0 3 8//,/p 3/ 2 w WN 4 w. a 2 M i July 2, 1940. o. WITTEL FOCAL PLANE SHUTTER 3 Sheets-Sheet 3 Original Filed April l2, 1938 FIG. 8

OTTO W/TTEL lNVENTOR ATTORNEYS BntentadJnlyZ 1940 PATENT OFFICE rocar. mun snu'rrsn.

Otto Wittcl. Rochester, N. Y., alaignor to man Kodak company, poration of New Jersey East- N. Y., a corapplication All! 12, 1m, Serial No.

Original 201,589. Divided and this application Novemher 23. 1938, Serial No. 242,080

'IOlaims.

The present invention relates to a blind type focal plane shutter for photographic cameras, and particularly to a focal plane shutter of the type wherein the following blind is released by the unwinding of the leading blind to give the desired exposure slot between the ends-of said two blinds, the width of said slot being thus altered for obtaining the desired shutter speeds.

This application is a division of my co-pending application Serial Number 201,539, filed April 12, 1938, and entitled Shutter setting and film winding mechanism.

In focal plane shutters of the type including a leading blind and a following blind the shutter speed is determined by the width of the slot maintained between the adjacent ends of said two blinds as they move across the exposure aperture of the camera. In known focal plane shutters of this type it has been common to obtain the desired width of exposure slot when the two blinds are wound up, in which case the following blind is permitted more winding up than the leading blind, or the slot has been obtained by having the two blinds wound up in an overlapped condition, then first releasing the leading blind which in turn automatically releases the following blind after a given interval to give the desired width of slot between their adjacent ends. In either case the means for adjusting this width of exposure slot includes a movable speed setting member on the exterior of the camera adjustment of which serves to alter the operable connection between the winding means for the two.

blinds so that an adjustment thereof will give the desired exposure slot either at the time the blinds are wound up or at the time they are released. With speed setting arrangements commonly used this speed setting member on the exterior of the camera is so connected with the shutter blinds or the winding means therefor that it is moved when the blinds are being wound up, moved when the blinds are unwinding, or at both times. Such movement of the speed setting member has been found to be undesirable, because it lends itself to incorrect exposures. This is true, because if the arrangement is such that a movement of the speed setting member takes place at the time the blinds are being wound up or are unwinding, and this movement of the setting member is unintentionally interfered with by the operator, the movement of the two blinds will not take place as intended. This is most apparent with arrangement, where the speed setting member moves as the two blinds are released or move to their unwound positions. In this case any interference with the moving setting member will either retard the speed of movement of the exposure slot across the exposure aperture below that provided for by the wind-off springs, or may effect an undesired variation in the width of the exposure slot depending of course upon the particular connection between the blind moving means and said speed setting member.

It will be appreciated that since this speed setting member must necessarily be placed on the exterior of the camera in an accessible place for its intended adjustment, it will be so positioned as to be easily interfered with unintentionally.

Therefore; one object of the present invention is to provide a focal plane shutter of the type including a leading blind and a following blind wherewith the speed setting member for determining the width of the exposure slot between the ends of the two blinds is not moved in conjunction with movement of said blinds to either their wound up or unwound positions. Another object is to provide a focal plane shutter of the type described wherewith the speed setting member may be adjusted to a given speed setting at any time after the shutter is completely unwound and before it is released from its wound-up condition. And a further object is to provide a focal plane shutter of the type described wherein the ends of the two blinds are adapted to be in an overlapped condition when completely wound up and the desired exposure slot is formed when the following blind is released by movement of the leading blind. And yet another object is to provide such a focal plane shutter wherein the speed setting member is rotatable in a single plane, and is not moved axially to or from the camera. A further object is to provide a focal plane shutter of the type described in which the speed setting member includes a motion transmitting member which is moved axially of the setting member by the winding means for the leading blind to release the following blind without eflecting a movement of said speed setting member. And anotherobject is to provide a focal plane shutter of the type described having a speed setting arrangement which is simple and efficient in operation, and adapted for use in a limited space.

Briefly, the present invention comprises a blind type focal plane shutter wherein the leading and following blinds are held in their wound-up positions by separate catch means, the leading blind being released manually and the following blind being released automatically by the wind-up pulley for the leading blind after the same has made a given part of a revolution in winding-off. The release of the catch for the following blind is efiected when a motion transmitting member adapted to be rotated relative to said wind-up pulley by a speed setting member is moved axially of said speed setting member by a projection on said wind-up pulley.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof. will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which,

Fig. 1 is a top plan view of a camera embodying this invention,

tion, of one end of the camera with the topplate removed, and showing the planetary gear-. ing between the winding knob, takeup spool, and the wind-up drum of the shutter,

mg. 2 is an enlarged plan view. partly in sec-' Fig. 3 is an enlarged sectional elevation of one end of the camera showing the connection between the wind-up drum, the takeup spool, and the winding knob,

Fig. 4 is a partial rear elevation of a camera with the back removed for loading, and showing the film measuring mechanism, r

Fig. 5 is a section taken substantially on line 5-6 of Fig, 2, and showing the release for the following blind operated from the speed setting mechanism,

Fig. 6 is an enlarged plan view of the camera with the top plate removed,

Fig. 7 is a section taken substantially on line 1-1 of Fig. 6, and showing the shutter release mechanism,

Fig. 8 is an elevation, partly in section, of the shutter curtains separated from the enclosin part of the mechanism and in a somewhat diagrammatic form,

Fig. 9.is a section taken substantially on line 3-4 of Fig. '7, and

Fig. 10 is a detail of the slide which is part of the film measuring mechanism, and which stops the takeup spool after a given length of film has been advanced.

Like reference characters refer to corresponding parts throughout the drawings.

A focal plane shutter constructed in accordance with a preferred embodiment of the present invention is shown mounted in a compact camera wherein a camera body I, having film spool chambers 2 and 3 for the supply and takeup film spools I and 5 respectively, has a back or closure 3 which is removable from the camera body for loading the film into the camera. The camera objective is carried in a lens mount 1 which can be mounted on the camera body in any suitable manner so as to be received within the same for carrying purposes, i. e. folding bed and bellows, telescoping lens mount, etc., and for the purpose of illustration I have shown a camera constructed so as to receive the lens mount in telescopic relation in a recess in the front of the camera whereby it is adapted to be received in the recess 3 in the camera body when collapsed. This recess 3 has arcuate portions 3' which may be internally threaded with threads of steep pitch, and in threaded engagement with which the mount may be arranged so as to be screwed into and out of the camera body. Since the method of mounting the lens on the camera body has no bearing on the present invention, the particular structure used is of no consequence, and is not specifically shown in the drawings.

Behind the recess 3 is situated a frame 9 having a rectangular aperture III equal in size to the picture which is to be taken. The aperture It in the frame 3 will be equal in dimension to the rectangular outline of the recess 3 into-which the lens mount telescopes, and will serve to prevent the lens upon telescoping to its retracted position from accidentally engaging the shutter curtains. This frame may be fastened to the camera body i by screws iii, and is provided with ears ii for supporting the stub shafts l2, see Fig. 4. Situated in the camera body i behind and spaced from the frame 9 is the customary film guide plate i3 over which the film F is threaded in moving from the supply spool 4' to the takeup spool 3. This plate l3 may be grooved to receive the filmstrip to properly position it in the focal plane of the lens, and is provided with an exposure aperture M which determines the picture size on the film, and into a position relative to which the film is moved for exposure.

While the focal plane shutter may be of any well-known type, for the purpose of illustration I have shown one of the two-curtain type, generally known as a self-capping shutter. The wind-up drum for the shutter includes a shaft l6 which extends across the camera body i and is rotatably mounted in a recess ii in said camera body. One end l8 of the shaft i6 is rotatably mounted in the bore iii of the stud it, which stud in turn extends through and is rotatably mounted relative to the sleeve extending through and fixed to the top wall II of the camera body by the fiared portion 22. The other end 23 of the shaft I6 is rotatably mounted in the bearing 24 fixed to the inside face of the bottom wall 25. Pinned to the shaft 16 adjacent the ends trunnions 28 and 23 respectively. Rotatably mounted relative to the shaft it and spaced therefrom by hearing sleeves 30 is a wind-up roller 3i which has a reduced hollow shank 32 and enlarged curtain supporting ends 33 and 34.

The front or leading curtain 35 has one' end fastened to the spring roller 36 onto which it is wound in winding oil, and the other end thereof is provided with a cross strip 31 to the ends of which are fastened cords 38 fixed to and passing over the wind-up pulleys 26 and 21. The cords 33 pass over guide pulleys 38 in passing to windup pulleys 26 and 21, these guide pulleys being located so as to direct the curtain 35 in a path parallel to the plane of the exposure aperture. The rear or following curtain 40 is cut out at one end to provide straps 4i which are attached at their ends to and pass over curtain supporting ends 33 and 34 of the wind-up roller 3i. The other end of the curtain 40 is provided with a cross Strip 4! to the ends of which are fastened cords 43, the free ends thereof being fixed to spring operated pulleys 44 adjacent the spring roller 33, see Figs. 6 and 8. In passing to the spring pulleys 44 the cords 43 pass over guide pulleys 43 coaxial with the spring roller 36 so as to maintain the curtain 40 parallel to the other curtain. These guide pulleys 45 are rotatable with respect to the spring roller 38, and are not aflected by the spring action thereof at any time.

The top end of the following curtain III is maintained in parallel relation with the exposure aperture and properly guided onto the .40 thereof are wind-up pulleys 26 and 21 having' '15 d tainsarejwound up togt her. The width of thewind-up roller by passing over the guide rollers 48 which may be rotatably mounted on the stub shafts l2'supported by the frame member I,

fwhichfguide rollers-are coaxial with the guide "pulleysjl'and are of thesame diameter and in alignment; with the lower guide pulleys 4| for;

thefollowing curtain. Referring to Fig. 8,v it

the ends of the curtains are separated to prouniformly across the exposure aperture to give -the.-i.desired exposure.

} I When the curtains are woundjup, ,.the following-curtain 48 moves first enough to close the slotsv after which both cur- ..slot is variable to give different exposures. and

following curtain 48 is wound up on the wind-up "the mechanism for controlling the width of the slot. as well as the proper winding up of the curtains, will be described hereinafter. Sincethe miller, and the leading curtain II is wound upon the wind-up pulleys 28 and 21, it will be appreciated that both must be operated to windup or set the shutter. Therefore. since the wind-up pulleys 25 and 21, and the wind-up roller ii are connected to be operated from the same winding means, and are both actuated to wind up the shutter, the'o'ombination of the two can be referred to as the wind-up drum for the shutter when speaking of the shutter as a single element.

For winding up, or setting the shutter, and releasing the same, the following mechanism is provided. Rotatably mounted on the bearing 24 against the bottom wall 25 of the camera body is a spur gear 41 rotation of which drives the wind-up shaft to wind up the shutter. To the inside face of the spur gear 41 is attached a plate 48 having a. spring finger 48 pressed away therefrom to engage a pin 58 extending from the face of the wind-up pulley 21, see Figs. 3 and 9. Thus when the spur gear 41 is rotated in the direction as indicated by the arrow in Figs. 3 and 9, the spring finger 48 picks up the pin and causes rotation of the wind-up pulleys 26 and 21, and the shaft l5 connecting the same. This rotation serves to wind-up the leading curtain 35. Referring to Fig. 3, it will be noticed that a pin 52 extending radially from the trunnion 29 of the pulley 21 abuts and picks up pin 53 extending axially from the curtain supporting end 34 of the wind-up roller 8| so that the windup roller 3| is rotated along with the wind-up pulley when the spur gear 41 is rotated in the right direction. This serves to wind up the following curtain in conjunction with the winding up of the leading curtain. In the drawings, with the exception of Fig. 8, the parts are shown in the position they will assume when the shutter is wound up or set, and this position is automatically determined when the projecting end 54 of the plate fixed to the inside face of the wind-up pulley 21 engages the stop member 58 fixed to the camera body and extending radially into the recess H. To prevent the spur gear from rotating in the wrong direction due to the spring tension on the shutter, I have shown a spring 51 fixed in the recess l1 to ride on the teeth of the spur gear 41 in the manner of a pawl and ratchet. It is to be understood that this effect can be obtained by placing a one-way clutch mechanism between the gear 41 and the bearing therefor.

The pins 52 and 53 on the wind-up pulley 21,

and on the wind-up rollers 8| respectively are so positioned relative to one another that when they are in driving abutment the leading and following curtains .are in an overlapped position so that they prevent all passage of light through the exposure aperture. The curtains will be in this relation from the time they are completely --wound oil' until they are completely wound up. 'Theshutter is releasedflwhen the spring finger 48 jattachedto thespur gear 41 is removed from 'thepathof thepin' 54 on the wind-up pulley 21 whereupon the spring roller 25 and the spring operated pulley 44-actto pull the curtains 85 and across the exposure aperture l4 at a uni- 4 form speed and with a given slot S between the ends-of the two. The width of the slot S may be varied'by a speed setting mechanism which will be described, hereinafter.

-In winding'oif, the travel of the leading curtain'jli will be stopped when the pulley 21 makes practically a complete revolution and the pro- Jection '4 of the plate 55 abuts the opposite side of the stop member 55. The travel of the following curtain 48 will be stopped when the pin 52 on the trunnion 28 completes practically a complete revolution to abut the pin 58 on roller 3| in which pomtion the curtains will be overlapped and in position to be wound up in such overlapped position. The shutter release includes a push rod 51 extending through the camera body i adjacent the shutter wind-up drum and slidably supported at its opposite ends. The push button 54 is attached to this push rod 51 and extends to the outside of the tending from the push rod ear 41 is an arm 58 which an extension it formed on see Fig. 9. When the push button 58 is pressed downwardly, the push rod 51 is slid parallel to the axis of the wind-up drum and the arm 59 thereon presses against the extension 60 and springs the spring finger 49 out of engagement with the pin 58 whereupon the shutter is allowed to wind oil. The push rod 51 is normally moved to its inoperative position by a coil spring 6i which has one end engaging a hole in the push rod while the other end thereof is held by a pin 82 fixed to the supporting plate 88 in the camera body I. The extension 58 is required on the spring finger 48 because of the limited nature of the space available between the spring finger and the wind-up pulley does not permit the arm 59 to extend far enough to engage the finger proper without interfering with the pulley 21. It will be noticed by referring to Fig. 7 that this extension 68 extends beyond the periphery of the pulley 21 so that the arm can engage the same without interfering with the pulley.

Coming now to the arrangement for winding the film and shutter from the same winding knob, it will be noticed, by referring particularly to Figs. 2 and 3, that the winding knob is fixed to the stub shaft 56 extending through and rotatable relative to the camera wall 2| by the screw 81. Although it has not been shown or described, this stub shaft 66 may be provided with a one-way clutch which would serve to allow rotation of the winding knob 65 in only the proper direction, that indicated by the arrow in Fig. 1. On a reduced end 88 of the stub shaft 88 is rotatably mounted a sleeve member '68 integral with one end of which is a gear" and integral with the other end of which is a radially extending flange H the periphery of which is provided with ratchet teeth 12. The sleeve memcamera body. Ex- 51 adjacent the spur is adapted to engage the spring finger 48,

ber 69 is rotatably held on the reduced end 68 or the stub shaft by the bolt 13. The outer face of the fiange II is provided with a pair of lugs 14 which are diametrically opposite one another and form a key which fits into the customary keyway in the end of the takeup film spool 5 to drivingly connect the same to the flange II. The other end of the film spool is placed on a stud l5 fixed to and extending from the bottom wall 25 of the camera body, and relative to which the spool is rotatable. This manner of mounting a takeup spool in a camera to be drivingly connected to the winding key is well known in the art, and I have only modified said construction by drivingly connecting the spool to the sleeve member 69 instead of directly to the winding key proper.

Fixed to and rotatable with the stub shaft 66 is a flange 16 from which extends a plurality, in this case four, of studs 11 to the other end of which is fixed an annular ring 18. These studs 11 are circumferentially spaced around the flange 15 relative to one another, and rotatably' mounted on each stud between the flange l6 and the annular ring I8 is a pinion 19 which meshes with the gear 10 fixed to the sleeve member 69. Rotatably mounted between the flange 16 and the annular ring 18 is a ring gear 88, and this ring gear is of such size that, when mounted as described, the internal teeth 8| thereof mesh with the teeth of each of the pinions 19. The external teeth 82 of the ring gear 80 mesh with a pinion-83 fixed to the shaft 84 rotatably mounted in the top and bottom walls 2| and 25 of the camera, and rotation of this shaft is transmitted to the spur gear 41 through engagement of said spur gear with the gear 85 fixed to the other end of the shaft 84. With this described planetary gearing arrangement the shutter can be wound up and the film can be advanced through rotation of the winding knob 55 each independently of the other. For instance, when the winding knob is rotated in the direction indicated by the arrow in Fig. 1, either the shutter wind-up drum or the film takeup spool will be rotated first, depending upon which offers the least resistance to movement, until it has been fully wound after which further rotation of the winding knob will serve to wind up the other to its full wound-up position. When both the shutter and film have been wound up and have come to a stop, the winding knob will be locked against further rotation thereby giving an indication that these steps have been accomplished.

By way of explaining the action of this planetary gearing, let us assume that an exposure has just been made and the shutter is ready to be set and the film is to be advanced. Assuming that the shutter offers the least resistance to movement, when the winding knob 65 is rotated the pinions 19 will be rotated around the gear 10, which is connected to the takeup spool 4, and the ring gear 80 will be rotated by rotation of said pinions to drive the spur gear 41 and wind up the shutter until the projection 54 on the pulley 21 engages the stop member 56 in which position the shutter is fully wound and can be wound no further. Now since the gear train driven by the ring gear 80 and the ring gear itself is held against further movement, upon continued rotation of the winding knob 65 the pinions I9 will run around the inside of the ring gear and will drive the gear 10. This causes rotation of the sleeve 69 and along with it the flange II to which the takeup spool 4 is keyed, so that the film is wound. The winding knob 65 can be rotated until the sleeve 69 is automatically stopped and positively held against further rotation through the action of a film measuring mechanism described hereinafter. When both the shutter wind-up drum and the takeup spool have been advanced the required amount and are positively held against further movement, both the ring gear 80 and the gear 10 are held against rotation so that the pinions 19 cannot be rotated around the axis of the stub shaft 68 and the winding knob is therefore locked against further rotation. It will be readily understood by those skilled in the art that should the resistance to movement be equal in the film winding and shutter winding mechanisms, that rotation of the pinions 19 by knobs 65 will cause both the ring gear 80 and the gear III to rotate in the proper direction, see arrows in Fig. 2, at the same time. Under these conditions the film will be advanced and the shutter will be wound simultaneously until the resistances in the two become unequal whereupon one will move while the other stands substantially still, as described above. It is pointed out that one or more pinions 18 may be used and function as described, but I have found that four spaced as shown give a most satisfactory result in that binding between the ring gear 80,,gear I0, and the pinions I9 is eliminated.

Referring now particularly to Figs. 1, 4, 6, and 10, the film measuring and exposure counting mechanism includes a film measuring roller 81 which extends across the camera body in the path of the film F and which is rotatably mounted at either end in supporting plates 88 positioned in the camera body. This measuring roller is substantially equal in Width to the film strip, and, either end of the roller is provided with flanges 89 the peripheries of which are roughened in any suitable manner, as by knurling. The film, which is unperforated, in passing from the supply spool to the takeup spool is supported at its edges by these roughened flanges so that movement of the film serves to rotate said measuring roller. It is absolutely essential in measuring the film advance that there be no slippage between the film strip and the measuring roller, hence the reason for roughening the flanges of said roller. Further assurance againstv slippage at this point is provided by the spring fingers 90 which are mounted in the camera body and engage each edge of the film adjacent said measuring roller to press the edges of the film into engagement with said rough flanges. Most cameras of this type, where the film advance is controlled by a measuring roller, are adapted for use with film which is perforated along its edges, and wherewith the measuring roller can take the form of a toothed sprocket to positively engage these perforations. With this type of structure there is no chance of slippage between the measuring roller and the film strip, and the measuring roller is usually geared to the shutter winding mechanism so that the film is fully advanced and the shutter is set simultaneously in which case no differential drive between the two is needed. However, it will be readily appreciated that where unperforated film is used, as in this instance, this positive drive between the film and measuring roller is not manifest, and to overcome the effect of any slippage which might cause the fi1m wind up to lag behind the setting of the shutter, a differential drive of the type described is indispensable.

Rotatable with the measuring roller is a pinion 9I which is in engagement with a gear 92 to the face of which is fastened a disk 93 having a slot 94 extending radially from the periphery thereof toward the center thereof. Slidably mounted on a partition 95 adjacent the top wall 2| of the camera is a slide 96 which has a down turned projection 91 which is adapted to engage the slot 94 in the disk 93 when the film has been wound, see Fig. 6. The end of the slide is provided with an offset arm 96 the end 99 of which acts as a pawl to engage the ratchet teeth 12 of the periphery of the flange II to hold the film takeup spool 4 from rotating.

The slide 96 is normally spring pressed into the position shown by a spring I00, in which position the projection 91 and the end 99 of-the arm 96 engage the ratchet teeth I2 and the slotted disk 93 to automatically stop and hold the takeup spool against rotation. Movement of the slide 96 to the locking position shown depends upon the disk 93 being in the position where the projection 91 is admitted to the slot 94 in the disk 93, and since this disk is rotated from the film measuring roller 61 the slide can move to this position only after a given length of film has been advanced. Before the film can be advanced after an exposure, the slide 96 must be moved against the spring I00 to disengage the projection 91 from the slot 94 in the disk and to remove the end 99 of the slide 98 from the ratchet teeth I2. This movement of the slide is effected by pressing against the button IOI connected to the slide and extending through a slot in the camera wall 2| to the outside thereof. Movement of the slide is limited in each direction by the length of the slot I02 in the slide 96 in which slides a pin I03 projecting from the partition 95. As the slide 96 is moved to release the projection 91 from the slot 94 in the disk,

the tension in the film will serve to move the l measuring roller 81 a suflicient amount to cause rotation of the disk to a position wherein the slot is just out of alignment with the projection 91. With the projection thus engaging the periphery of the disk, the slide will be held in a retracted position against the action of the spring I00 wherein the end 99 of the arm 90 will be moved from engagement with the ratchet teeth I2. The slide will be held in this retracted position until the disk 93 makes one complete revolution and the slot 94 therein comes again into alignment with the projection 91, whereupon the slide will return to its locking position. The gearing between the measuring roller 81 and the disk 93 will be such that the advance of a given length of film over the roller will cause one rotation of the disk after which the slide 96 will automatically move to its locking position, and I have found that a 2 to 1 ratio between the pinion 9I and the gear 92 driving the disk will give a satisfactory relation between the measuring roller and the disk 93.

The exposure counter includes a numbered knob I05 which is rotatably mounted on the top wall 2| of the camera. This knob is rotatably mounted on a shaft I06 extending through the camera wall and to the lower end of which is mounted a ratchet IN. This ratchet is engaged and held against rotation in the wrong direction by a spring pressed pawl I08 pivoted at I09 to the under side of the camera wall 2|. A finger H0 is mounted to slide with the slide 96, having a round end III integral therewith set into a circular recess H2 in the edge of the slide 96, and this finger engages the ratchet I01. By means of this construction it will be understood how the sliding movement of the slide 96 after each advance of the film will serve to move the ratchet member I01 through one step to cause the partial rotation of the knob I05 and thereby indicate an exposure. After the new film has been threaded into the camera, counter knob I05 will be set to zero with a fixed index mark on the camera wall, and thereafter at each winding of the film the counter will be rotated step by step to give the operator an indication of how many exposures he has made on the roll of film in the camera.

To control the exposure, the width of the slot S between the ends of the leading and following curtains 35 and respectively, in moving past the exposure aperture I4 in winding off, is varied to let through different quantities of light. According to the present invention this exposure control, or shutter speed as it may be called, is effected in the following manner. Referring to Figs. 3, 5, and 'I, an apertured plate H4 is slidably mounted on the sleeve 20 extending through the wall 2| of the camera body, and has attached thereto a finger II6 which extends parallel to the axis of the wind-up roller SI and adjacent the periphery of the curtain supporting end 33 thereof. Also to the edge of the aperture plate H4 is attached one end of a rod II6 which is slidably mounted at its opposite ends in the supporting plates 06. A coil spring II 8 surrounding the rod H6 and located between a shoulder II9 fixed thereto and one of the supporting plates 69 normally forces the rod H6 and along with it the plate H4 and the finger II5 to the left, looking at Figs. 5 and '7. It will be readily understood by referring to the drawings, that since the rod I I6 is supported at both ends, this structure tends to hold the plate I I4 in a horizontal position and allows the same to slide along the sleeve 20 without binding.

Fixed to and extending radially from the curtain supporting end 33 of the wind-up roller 3| is adapted to extend when the curtain is wound up; In winding up, the round side of the pin I20 is adapted to engage an inclined end on the finger H5 to cam the same to the right and allow the pin to pass thereby, but after the pin passes said finger a flat side thereon engages the square side of the finger and the roller 3| is held in a wound up position by said finger.

Integral with the stud I9 and located between the face of the wind-up pulley 26 and the aperture plate II 4 is a flange I42. This flange is provided with a ball seat in which is loosely located a ball I23, the surface of which contacts both the face of the pulley 26 and the face of the aperture plate II4. Located on the face of the pulley 26 is a semi-circular member I24 which is adapted, when the pulley rotates, to engage the ball I23 and force the same against. the aperture plate II4 to thereby slide the plate along the sleeve 20 and remove the finger II6 from the path of the pin I20 on the end 34 of the windup roller 3|. By means of this arrangement, when the curtains 35 and 40 are wound up and in a position shown, the movement of the shutter release button 58 causes the push rod 51 to disengage the spring finger 49 of the pin 50 on the wind-up pulley 21, whereupon the leading curtain is released and starts to wind off. After the leading curtain is moved a given distance the semi-circular member I24 of the wind-up pulley 26 engages the ball I23 and effects the release of the finger II5 from the path of the pin I20 whereupon the following curtain is released and allowed to wind off. The delay between the release of the leading curtain and the following curtain determines the width of the exposure slot S between the ends of the curtains as they pass the exposure aperture.

It will be readily understood that this delay can be varied by altering the relative position of the ball I23 with respect to the semi-circular member I24 when the curtains are in a woundup position, or when the curtains are in any relative position. This relationship between the ball I23 and the semi-circular member I24 may be optionally altered by turning the shutter setting knob I25 pinned to the end of the stud I9 projecting to the outside of the camera, which serves to rotate the flange I42 and along with the ball I23 relative to the pulley 26. The setting knob may be marked with a plurality of speedindications around its periphery which when aligned with a fixed index on a camera wall will serve to indicate the speed for which the shutter is set.

With this arrangement for setting the'shutter speeds, or the width of the slot S between the curtains moving past the exposure aperture, the setting knob I25 does not rotate as the shutter winds off, because there is no positive connection betwen the setting knob and the winding drum of the shutter. This, as will be appreciated, is a distinct advantage over previously used shutter setting arrangements where the setting knob rotates as the shutter winds off, where the shutter winds up, or both. Where the setting knob rotates with the shutter winding drum there is always a chance of the operator getting his fingers in the way of and interfering with said knob, which must necessarily be in an accessible position, and if this happens the winding off of the shutter is accidentally interrupted or entirely stopped and the exposure is either spoiled or is unsatisfactory due to an incorrect setting speed.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art, and by the spirit of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States is:

1. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading blind and a following blind, means normally acting to move each of said blinds across said exposure aperture, means for winding each of said blinds to their tensioned position, a manually releasable catch for holding said leading blind in its tensioned position, a releasable stop for holding said following blind in its set position, means operated by movement of said leading blind for releasing said stop after a given movement of said leading blind, said means including an actuating member on a rotating part of the wind-up means for the leading curtain, a

motion transmitting member connected to said stop and adapted to be engaged and moved by said actuating member after said leading blind is released to release said stop, a speed setting member for moving said motion transmitting member relative to the position assumed by said actuating member in the tensioned condition of the leading blind and in the path of movement of said actuating member, said motion transmitting member connected to said speed setting member to be capable of movement relative thereto as well as for movement therewith, whereby movement of said motion transmitting member to release said stop is independent of said speed setting member.

2. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading curtain and a following curtain, means normally tending to move each of said curtains across said exposure aperture, a wind-up pulley for the leading curtain, a wind-up roller for the following curtain, means for rotating said windup pulley and wind-up roller to their wound-up 'postions where the ends of said curtains are in an overlapping relation, a releasable catch adapted to engage and hold said wind-up pulley in its wound-up position, a releasable stop adapted to engage and hold said wind-up roller in its woundup position, manually operated means for releasing said catch to release the leading curtain,

means operated by the unwinding of said leading curtain for releasing said stop at a given interval after the release of said catch, whereby the desired width slot is provided between the ends of said curtains, said means including a projection on said wind-up pulley and extending axially thereof, a motion transmitting member movable axially of said wind-up pulley and normally held in the path of said projection to be engaged and moved by said projection when the wind-up pulley rotates, means for rotating said motion transmitting member relative to said wind-up pulley to alter the position of the same with relation to said projection when the wind-up pulley is in its wound-up position, said means including a speed setting member rotatably mounted on said camera to move over a speed scale on said camera, said motion transmitting member connected to said speed setting member so as to be rotatable therewith for rotation relative to said projection, and capable of movement relative to said speed setting member when transmitting motion to release said stop, whereby said speed setting member is adapted to remain stationary during movement of the curtains across said exposure aperture.

3. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading curtain and a following curtain, means normally tending to move each of said curtains across said exposure aperture, a wind-up pulley for the leading curtain, a wind-up roller for the following curtain, means for rotating said windup pulley and wind-up roller to their wound-up positions where the ends of said curtains are in an overlapping relation, a releasable catch adapted to engage and hold said wind-up pulley in its wind-up position, releasable stop adapted to engage and hold said wind-up roller in its woundup position, manually operated means for releasing said catch to release the leading curends of .said curtains, said means including a projection on said wind-up pulley and extending axially thereof, a holding member rotatably mounted relative to said wind-up pulley and located adjacent the end of said projection on said wind-up pulley but spaced therefrom, a motion transmitting member carried by said holding member to be rotated therewith but capable of axial movement relative thereto, said motion transmitting member located in the path of said projection and normally spring pressed toward the plane of movement of said projection to be engaged and moved by said projection when the wind-up pulley rotates, and a speed setting member rotatably mounted on the camera to move over a speed scale on said camera, said speed setting member connected to said holding member to rotate the same and along with it said motion transmitting member, relative to said projection in the wound-up position of the wind-up pulley, whereby the arcuate relationship of said motion transmitting member and said projection may be varied to give the desired interval between the release of the two curtains.

4. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading curtain and a following curtain, means normally tending to move each of said curtains across said exposure aperture, a wind-up pulley for the leading curtain, a wind-up roller for the following curtain, means for rotating said windup pulley and wind-up roller to their wound-up positions where the ends of said curtains are in an overlapping relation, a releasable catch adaptedto engage and hold said windup pulley in its wind-up position, a releasable stop adapted to engage and hold said wind-up roller in its wound up position, manually operated means for releasing said catch to release the leading curtain, means operated by the unwinding of said leading curtain for releasing said step at a given interval after the release of said catch, whereby the desired width slot is provided between the ends of said curtains, said means including a cam faced projection extending axially from one face of said wind-up pulley, a disc mounted coaxially with said wind-up pulley for rotation relative thereto,

and located adjacent the face of said wind-up pulley but spaced therefrom sufflciently to be free of said projection, said disc having an opening located radially of said disc a distance equal to the radial distance of said projection on the wind-up pulley, a ball located in said opening for movement axially of said disc, and extending into the pathof said projection to be engaged and moved axially of the disc thereby, means forcing said ball into the path of said projection, and a speed setting member rotatably mounted on said camera and connected to said disc for moving the same through a given are of movement, whereby the arcuate relationship of theball and projection may be varied to give the desired interval between the release of the two curtains.

5. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading curtain and a following curtain, means normally tending to move each of said curtains across said exposure aperture, a wind-up pulley for the leading curtain, a wind-up roller for the following curtain, means for rotating said windup pulley and wind-up roller to their wound-up positions where the ends of said curtains are in an overlapping relation, a releasable catch adapted to engage and hold said wind-up pulley in its wound-up position, manually operated means'for releasing said catch to release the leading curtain, a releasable stop adapted to engage and hold said wind-up roller in its wound-up position, and adapted to release said wind-up roller upon being moved axially of said wind-up roller, means normally holding said stop in its engaging position, means operated by the unwinding of said leading curtain for releasing said stop at a given interval after the release of said catch, whereby the desired width of slot is provided between the ends of said curtains, said means including a cam faced projection on said wind-up pulley and extending axially thereof, a motion transmitting member-movable axially of said wind-up pulley, and normally held in the path of said projection, to be engaged and moved thereby when the wind-up pulley rotates, by the resilient means normally acting to hold said stop in its engaging position, means for causing axial movement of said motion transmitting member to effect a movement of said stop axially of said wind-up roller to its releasing position, and a speed setting means for rotating said motion transmitting member relative to said wind-up pulley to alter the arcuate relationship of the same with respect to said projection when the wind-up pulley is in its wound-up position, whereby the interval of time between the release of the two curtains can be varied to give the desired width exposure slot between the curtain ends.

6. A focal plane shutter for use in a camera leading curtain, a releasable stop adapted to engage and hold said wind-up roller in its wound-up position, and arranged to move axially of said roller in moving to its release position, resilientmeans normally acting to force said stop into its engaging position, means operated by the unwinding of said leading curtain \for releasing said stop at a given interval after the release of said catch, whereby the desired width of slot is provided between the ends of said curtains, said means including a cam faced projection on the face of said wind-up pulley and extending axially therefrom, a disc having an opening extending therethrough and mounted coaxially with said wind-up pulley for rotation relative thereto, and spaced from the face of said pulley a sufllcient distance to'prevent contact between the same and said cam faced projection on the pulley, a motion transmitting member located in said opening in said disc and capable of axial movement relative to said disc, said member arranged so that one end lies in the path of the projection on said wind-up pulley to be engaged and moved axially of the wind-up pulley by said projection as the pulley rotates in unwinding, the other end of said motion transmitting member adapted to engage and move said stop to its release position when axially moved by said projection, and a rotatable speed setting member fixed to said disc-for rotating the same whereby the angular relationship of said projection and motion transmitting member can be selectively varied to give the desired interval between release of the two curtains.

7. A focal plane shutter for use in a camera having an exposure aperture, and comprising a leading curtain and a following curtain, means normally tending to move each of said curtains across said exposure aperture, a wind-up pulley for the leading curtain, a wind-up roller for the following curtain, means for rotating said windup pulley and wind-up roller to their wound-up positions where the ends of said curtains are in an overlapping relation, a releasable catch adapted to engage and hold said wind-up pulley in its wound-up position, a manual push rod extending to the outside of the camera for releasing said catch to permit the leading curtain to wind oil, a releasable stop adapted to engage and hold said wind-up roller in its wolmd-up position, said releasable stop adapted to move axially of said roller in moving between its releasing and engaging positions, and including a plate co-axial with said wind-up pulley, resilient means normally acting to force said stop into its engaging position and said plate toward one face 0! said wind-up pulley, means operated by the unwinding of said leading curtain for releasing said stop at a given interval after the release of said catch, said means including a disc having an opening extending'therethrough and mounted co-axially with said wind-up pulley for rotation relative thereto, and situated between the face or said pulley and said plate forming part of said stop, a ball located in the opening in said disc and capable of axial movement relative to said disc, said ball being of a size whereby the suriace thereof contacts both the face or said pulley and said plate, a cam faced projection extending axially from the face of said pulley and adapted to engage and move said ball axially of said disc when said pulley unwinds, whereby said plate is moved axially of the windup roller to release said stop and permit unwinding of the falling curtain, and a speed setting knob rotatably mounted on the outside of said camera and connected to said disc for rotating the same to alter the angular relationship between said ball and said projection in the wound-up position of said pulley.

OTTO WI'ITEL. 

